This study is based on the hypotheses that: 1) alterations in salivary gland function are associated with the progression of HIV infection and these alterations predispose to oral candidiasis; 2) with increasing severity of HIV infection, patients develop Sjogren's Syndrome-like features. The study will cross-sectionally and longitudinally determine salivary gland changes at the different stages of HIV infection, it will determine the changes in salivary anti-candidal activities with the progression of HIV infection, and will determine the similarities and differences in salivary gland function of HIV-infected patients in comparison to those with Sjogren's. The study will utilize age- and sex-matched sero-negative controls and patients at different stages of HIV infection.